Artists can use software to create musical arrangements. This software can be implemented on a computer to allow an artist to write, record, edit, and mix musical arrangements. Typically, such software can allow the artist to arrange files on musical tracks in a musical arrangement. A computer that includes the software can be referred to as a digital audio workstation (DAW). The DAW can display a graphical user interface (GUI) to allow a user to manipulate files on tracks. The DAW can display each element of a musical arrangement, such as a guitar, microphone, or drums, on separate tracks. For example, a user may create a musical arrangement with a guitar on a first track, a piano on a second track, and vocals on a third track. The DAW can further break down an instrument into multiple tracks. For example, a drum kit can be broken into multiple tracks with the snare, kick drum, and hi-hat each having its own track. By placing each element on a separate track a user can able to manipulate a single track, without affecting the other tracks. For example, a user can adjust the volume or pan of the guitar track, without affecting the piano track or vocal track. As will be appreciated by those of ordinary skill in the art, using the GUI, a user can apply different effects to a track within a musical arrangement. For example, volume, pan, compression, distortion, equalization, delay, and reverb can some of the effects that can be applied to a track.
Typically, a DAW works with two main types of files: MIDI (Musical Instrument Digital Interface) files and audio files. MIDI can an industry-standard protocol that enables electronic musical instruments, such as keyboard controllers, computers, and other electronic equipment, to communicate, control, and synchronize with each other. MIDI does not transmit an audio signal or media, but rather transmits “event messages” such as the pitch and intensity of musical notes to play, control signals for parameters such as volume, vibrato and panning, cues, and clock signals to set the tempo. As an electronic protocol, MIDI is notable for its widespread adoption throughout the industry.
Using a MIDI controller coupled to a computer, a user can record MIDI data into a MIDI track. Using the DAW, the user can select a MIDI instrument that can be internal to a computer and/or an external MIDI instrument to generate sounds corresponding to the MIDI data of a MIDI track. The selected MIDI instrument can receive the MIDI data from the MIDI track and generate sounds corresponding to the MIDI data which can be produced by one or more monitors or speakers. For example, a user may select a piano software instrument on the computer to generate piano sounds and/or may select a tenor saxophone instrument on an external MIDI device to generate saxophone sounds corresponding to the MIDI data. If MIDI data from a track is sent to an internal software instrument, this track can be referred to as an internal track. If MIDI data from a track is sent to an external software instrument, this track can be referred to as an external track.
Audio files can be recorded sounds. An audio file can be created by recording sound directly into the system. For example, a user may use a guitar to record directly onto a guitar track or record vocals, using a microphone, directly onto a vocal track. As will be appreciated by those of ordinary skill in the art, audio files can be imported into a musical arrangement. For example, many companies professionally produce audio files for incorporation into musical arrangements. In another example, audio files can be downloaded from the Internet. Audio files can include guitar riffs, drum loops, and any other recorded sounds. Audio files can be in sound digital file formats such as WAV, MP3, M4A, and AIFF. Audio files can also be recorded from analog sources, including, but not limited to, tapes and records.
Manipulation of audio files often requires detecting transients. A transient is a short-duration signal that represents a non-harmonic attack phase of a musical sound or vocals. A transient contains a high degree of non-periodic components and a higher magnitude of high frequencies than the harmonic content of that sound. A common method of detecting transient events is to subtract the envelope amplitude of the audio signal from the Root Mean Squared (RMS) value at the time of the signal. Differences can be an indication for a transient event. However, this method has disadvantages in that the initial calculation of RMS and RMS in silent passages can lead to a significant number of false detections. Those of ordinary skill in the art would recognize that other conventional methods for detecting transients can lead to a significant number of false detections.